New research based on lab tests shows if you can deliver gold nanoparticles right
up to cancer cells during radiation treatment, more of the cells die.
The study shows that in principle, gold nanoparticles can intensify the killing power of radiation on cancer cells.
Writing in the Proceedings of the National Academy of Sciences, a team from
Brown University in Providence and the University of Rhode Island in Kingston, RI, says their proof-of-concept
study could lead to improved cancer treatments.
Treatments could be improved in two ways: either by using less radiation, thus
reducing adverse effects to patients, or by boosting the ability of current doses to kill
Nanotechnology is a relatively new and growing field where scientists can manipulate
nanometer-sized materials (nanoparticles) and tools that operate at the scale of
Previous studies have already shown that because of their unique properties, gold
nanoparticles can increase the effectiveness of radiation in killing cancer cells.
The gold nanoparticles act like tiny antennas that concentrate the radiation in the
area around them.
pHLIPs deliver gold nanoparticles right up to cancer cells
In this study, the team showed that using acid-seeking compounds called pH low-insertion peptides (pHLIPs) to deliver the gold nanoparticles right up to cancer cells,
they substantially increased the power of radiation to kill them.
The pHLIPs are important because they seek out the slightly more acidic malignant
cells and take the gold nanoparticles right up to them and tether them to their cell
membranes. The nanoparticles can only intensify radiation at a close range.
The study extends previous work by others from URI and Yale who invented pHLIP
technology. One of these was senior author of the new study Yana Reshetnyak, URI
professor in biological and medical physics, who explains the point of the further
“We previously demonstrated that pHLIP-nanogold particles could find and
accumulate in tumors established in mice. Now our task is to test if we can treat cancer
by irradiating tumors with nanogold particles more efficiently in comparison with
traditional radiation treatment.”
Studies based on theory and experiments show that gold nanoparticles absorb around 100
times more radiation than tissue. Because of gold’s unique properties, the radiation
causes the particles to release a stream of electrons into their immediate surroundings.
If this could happen in and very near cancer cells, they could suffer serious damage.
Irradiated cancer cells had 24% lower survival rate in presence of pHLIP-delivered
So in this new study, Prof. Reshetnyak and colleagues decided to bring together the
ability of pHLIPs to target cancer cells with the unique properties of gold
After crunching masses of complex calculations and running experiments, they
showed that cancer cells irradiated in the presence of pHLIP-delivered gold had a 24%
lower survival rate compared to those treated with radiation alone.
They also found that the pHLIP samples had a 21% lower survival compared to
irradiation with just gold but no pHLIPs.
The authors say these findings suggest the pHLIPs were effective in getting the gold
close enough to the cancer cells to do damage.
Lead author Michael Antosh, assistant professor of brain and neural systems research
at Brown, says:
“This study was a good proof of concept. We’re encouraged by our initial
results and we’re excited to take the next step and test this in mice.”
In December 2014, Medical News Today reported a study that suggests most elderly breast cancer patients receive unnecessary
radiation. In the journal Nature Methods, the authors say that despite
evidence supporting the omission of radiation treatment for elderly female patients with
early-stage breast cancer, nearly two thirds of them are still receiving it.